A succession of private equity buyers came and went.

Private equity buyers accounted for nearly a fifth of all deals in 2006, according to Thomson.

Viacom sold 18 percent to the public in 1999 and has been trying for several months to sell the rest to a private equity buyer.

Experts said ports businesses threw off a predictable amount of cash, a quality often attractive to private equity buyers.

Its stock is sagging and at least two private equity buyers are in talks to acquire the company.

"It was too attractive an asset for private equity buyers not to make a run at it," she added.

Private equity buyers often look for low-debt companies that are overspending, then they cut costs to increase earnings.

European telecommunications operators have become a target of private equity buyers in recent years.

Last year, the company earned $1.2 billion and generated a lot of cash that makes it attractive to private equity buyers.

And big private equity buyers are also increasingly active.